There is much in Blaenavon history for which the town and its residents should be proud, but its main claim to fame is the development of universally useable steel.
However, the history of Blaenavon began long before the Bessemer process was even conceived, and had been a centre of iron production since the year of the French Revolution, 1789, when production commenced in the North Street furnaces of the Blaenavon Company.
Wealthy industrialist Thomas Hill, with his partners Thomas Hopkins and Benjamin Pratt, recognized the potential of the rich coal and iron ore deposits around the Blaenavon area in 1782, and made the decision to first open a coal mine, and then an iron works in what was at that time a scattered hamlet of cottages.
The Blaenavon Company was soon sending iron all over the world and the town grew rapidly.
Carbon in Iron and the Bessemer Process However, the conversion of iron to steel was the nirvana of the iron industry, and the large-scale production of steel was not possible due to the large quantities of carbon in iron.
Blaenavon history is largely tied into the elimination of this.
For steel to be produced with consistent quality, iron had to be carbon-free and then fed with precise amounts of carbon and other elements to carbon-free wrought iron.
Henry Bessemer patented a process in 1855 that oxidized the carbon to its gaseous oxides, and also removed other impurities such as manganese.
However, the clay-lined Bessemer 'converter', as it was called, could not remove phosphorus, and the result was a form of steel too brittle for most uses.
Then Blaenavon came into the picture.
Phosphorus in Steel and Sidney Gilchrist Thomas Sidney Gilchrist Thomas, a Londoner with a Welsh father, was an industrial chemist who decided to tackle this problem of phosphorus in steel.
Believing that he had discovered a solution, he contacted his cousin, Percy Gilchrist, who was a chemist at the Blaenavon ironworks.
The manager at the time, Edward Martin, offered Sidney equipment for large-scale testing and helped him draw up a patent that was taken out in May, 1878.
Blaenavon history was now about to take off in earnest, because Sidney presented a paper on his invention to the Iron and Steel Institute in May 1879, and steel could now be made using high phosphorus iron.
This was of particular interest in Europe, where iron ore contained greater quantities of phosphorus than that from England and Wales, and European and other patents quickly followed.
Sidney Gilchrist Thomas's invention consisted of using dolomite or sometimes limestone linings for the Bessemer converter rather than clay and the phosphorus was converted to phosphates.
The process became known as the basic Bessemer process rather than the acid Bessemer process.
An additional advantage was that the process formed more slag in the converter, and this could be recovered and used very profitably as a phosphate fertilizer.
Blaenavon History and Iron and the Steel Explosion Blaenavon was now well and truly on the map, and many believe that Blaenavon history began with the Gilchrist Thomas system.
However, that is inaccurate: perhaps Blaenavon history was accelerated by the invention, but it certainly began in reality when the first pit was sunk and then the first of Blaenavon's eventual four furnaces went into production.
A whole infrastructure devoted to the iron and steel industry then grew up around the town, with forges and rolling mills being used to form the pigs and ingots needed to meet the requirements of the railway explosion in the UK and the USA.
Blaenavon iron traveled round the world, and the town became famous.
Industrial Landscape and World Heritage Status When Blaenavon received UNESCO World Heritage status in December of 2000, it was for the industrial landscape surrounding the town: the remains of the forges and iron ore works, the slag heaps of spent ore, and the remains of the horse tram system that cover the surrounding mountainsides, used to transport the iron down to the canal so it could be taken to Newport for shipping around the world.
Blaenavon history is a short one of only 250 years, yet it is a rich one of industrial and social development that affected the world in its heyday.
Blaenavon has recently enjoyed a resurgence and regeneration, but deserves more for the innovation, and for the iron and high-grade steel it produced for nigh on 115 years - the ironworks ceased production in 1904.
There was a brief revival in 1924, but it closed for good soon after.
It is now the largest and best maintained old ironworks of its type in Europe and a tourist attraction with free entry.
Blaenavon history, however, has not yet come to a close, and the UNESCO accolade has given it a lease of life that was as unexpected as it was welcomed.
The town has dusted itself down, shaken itself up and is ready to rumble!